The present invention relates to a method for development of silver halide photographic light-sensitive materials and in particular, to a method of development by which a useful high-contrast image can be stably obtained in the field of photomechanical process in graphic art printing.
In the field of photomechanical process, an image forming system which gives a photographic characteristic of high contrast (at least 10 in gamma value) is necessary for satisfactory reproduction of continuous tone images by dot images or for satisfactory reproduction of line images. Hitherto, for this purpose, a special developer called lith developer utilizing "infectious development" has been used, but this developer is highly susceptible to oxidation with air and has the defect of inferior stability with time since concentration of sulfites in this developer is much reduced (because a sulfite of high concentration hinders "infectious development").
Recently, there have been practically employed methods for obtaining high-contrast images by developing silver halide light-sensitive materials with a developer high in concentration of sulfite in the presence of hydrazine derivatives of amino compounds. For example, U.S. Pat. Nos. 4,224,401, 4,168,977, 4,166,742, 4,311,781, 4,272,606, 4,221,857, and 4,243,739 disclose methods of using hydrazine derivatives. Japanese Patent Kokai Nos. 56-106244, 61-267759, 60-258537, 61-230145, 62-211647 and 2-50150 disclose methods of developing with a developer containing an amino compound in the presence of a hydrazine derivative.
According to these methods, photographic characteristics of high contrast and high sensitivity can be obtained and besides, sulfite can be added to the developer in a high concentration and therefore, stability of the developer against oxidation with air is much improved than that of lith developer.
Addition of an amino compound to developer enhances activity of the developer, can accelerate the effect of hydrazine derivative to enhance high-contrast with a developer having a lower pH value than when no amino compound is added, and contributes to stabilization of the developer and rapid processing. However, since this effect of hydrazine derivative and amino compound to attain superhigh contrast is easily exhibited in the area where pH of the developer is higher than pH of conventional developer (11.0-12.3), they are, in many case, used in that pH range. Therefore, the diveloper is inferior to conventional developers in stability with time.